Cellular immune responses are required to limit the severity of recurrent HSV infection in humans. Initial genital HSV-2 infections are prolonged and severe, while recurrences are less severe and more frequently asymptomatic. Resolution of primary HSV-2 infection is associated with infiltration of antigen-specific T cells, including CD8+ cytotoxic T lymphocytes (CTLs). Serial lesion biopsy studies of recurrent HSV-2 infection in humans has shown a shift to CD8+ predominance as lesions mature and correlation of local CTL activity with virus clearance (Koelle, DM et al., J. Clin. Invest. 1998, 101:1500–1508; Cunningham, AL et al., J. Clin. Invest. 1985, 75:226–233). Thus, HSV antigens recognized by CD8+ CTL can be used for novel therapies and vaccines.
The complete DNA sequence of herpes simplex virus (HSV) is approximately 150 kb and encodes about 85 known genes, each of which encodes a protein in the range of 50–1000 amino acids in length. Unknown are the immunogenic epitopes within these proteins, each epitope approximately 9–12 amino acids in length, that are capable of eliciting an effective T cell immune response to viral infection.
There remains a need to identify specific epitopes capable of eliciting an effective immune response to HSV infection. Such information can lead to the identification of more effective immunogenic antigens useful for the prevention and treatment of HSV infection.